According to the article, this was by far the largest reported concentration of orb-weaver spiders. Spiderwebs were “as thick as a fire hose,” and in places the webbing was so dense it pulled 8-foot light fixtures out of place. (Shudder.)

Photo via Entomological Society of America

Apparently, these spider mega-cities tend to crop up in places near large water supply–which is probably why they all moved into the wastewater treatment plant.

There’s no word of how the plant managed to get rid of the spiders. Probably better not to know.